//The MIT License

//Copyright (c) 2009 Lluis Sanchez, Nick Darnell

//Permission is hereby granted, free of charge, to any person obtaining a copy
//of this software and associated documentation files (the "Software"), to deal
//in the Software without restriction, including without limitation the rights
//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//copies of the Software, and to permit persons to whom the Software is
//furnished to do so, subject to the following conditions:

//The above copyright notice and this permission notice shall be included in
//all copies or substantial portions of the Software.

//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//THE SOFTWARE.

using System;
using System.Reflection;
using System.Reflection.Emit;
using Polymorph.Properties;

namespace Polymorph
{
    /// <summary>
    /// The <see cref="CodeArrayLength"/> represents a length operation on an array.
    /// </summary>
    public class CodeArrayLength : CodeExpression
    {
        private CodeExpression m_array;

        /// <summary>
        /// Initializes a new instance of <see cref="CodeArrayLength"/> with the array
        /// expression to get the length of.
        /// </summary>
        /// <param name="array">The array expression to get the length of.</param>
        public CodeArrayLength(CodeExpression array)
        {
            m_array = array;

            if (!array.ResultType.IsArray)
                throw new InvalidOperationException(Resources.ArrayLengthOnly);
        }

        /// <summary>
        /// Generates the IL for the array length operation.
        /// </summary>
        /// <param name="gen">The IL generator to use.</param>
        public override void Generate(ILGenerator gen)
        {
            m_array.Generate(gen);
            gen.Emit(OpCodes.Ldlen);
        }

        /// <summary>
        /// Prints the humanly readable array length expression.
        /// </summary>
        /// <param name="cw">The code writer to use.</param>
        public override void PrintCode(CodeWriter cw)
        {
            m_array.PrintCode(cw);
            cw.Write(".Length");
        }

        /// <summary>
        /// Gets the result type for the array length operation.
        /// </summary>
        public override Type ResultType
        {
            get { return typeof(int); }
        }
    }
}